Neil Springer, QMI Agency

Junior dos Santos made his first successful defence of the heavyweight championship, earning a second-round TKO victory over Frank Mir in the main event of UFC 146 in Las Vegas on Saturday.

Dos Santos' boxing and takedown defence looked sharp, as he continually beat Mir to the punch and avoiding getting put on his back. The tough Brazilian hurt the former champ near the end of the first round, wobbling him with an overhand right, but was unable to put him away.

After countering a knee with a straight right that floored Mir in the second, dos Santos unloaded with strikes on the ground to secure the dominant victory.

Though dos Santos avenged Mir's win over his mentor, Antonio Rodrigo Nogueira, he said this fight wasn't personal.

"No, Nogueira is a tremendous fighter," dos Santos began. "Frank Mir is a really good fighter, too. That fight is between them. I respect my mentor, but I just came here to defend my belt -- and did it."

A disappointed Mir said he just couldn't keep up with dos Santos' speed.

"He's the champ," Mir said. "He's fast and I couldn't get out of the way. He hit me hard and there was a too many of them.

Silva never even got the chance to find his rhythm. The Strikeforce veteran threw one leg kick and immediately found himself flat on his back. Velasquez then went to town with elbows and punches in perhaps the nastiest bloodbath of the year.

"It's definitely a step in right direction," Velasquez said.

"My teammate Daniel Cormier fought Silva and he told us some stuff about when they fought."

The bout marks Velasquez's first since losing the heavyweight championship to dos Santos in November.

It only took one punch for Roy Nelson to get his hand raised against Dave Herman.

After a brief feeling out process, Nelson connected with devastating overhand right to secure the knockout at the 51-second mark.

Nelson was originally scheduled to face Silva on the card. When Silva was bumped up to face Velasquez, Nelson was paired with Gabriel Gonzaga, who suffered an injury.

Stipe Miocic spoiled Shane del Rosario's UFC debut.

After a rough first round that saw del Rosario unload with hard kicks, Miocic switched things up in the second and took the fight to the mat. Miocic then delivered a brutal series of elbows, cutting del Rosario open. After a number of unanswered shots, referee Yves Lavigne stepped in to halt the slaughter.